1. Technical Field
The invention relates to a process for manufacturing absorbent articles such as disposable pant diapers or diapers. The invention also relates to a product manufactured by the process. The process comprises the steps of continuously feeding a first web along a travelling path. The first web has a longitudinal direction coinciding with said travelling path and a transverse direction perpendicular to said longitudinal direction. The first web comprises a first and a second opposing strip extending in the longitudinal direction with a first panel portion therebetween. The process also comprises the steps of continuously feeding a second web along a travelling path. The second web has a longitudinal direction coinciding with said travelling path and a transverse direction perpendicular to said longitudinal direction. The second web comprises a third and a fourth opposing strip with a second panel portion therebetween.
2. Background Art
It has long been known to produce absorbent articles such as disposable pant diapers and diapers in an automated process plant. It is important to have speed in the process because the more absorbent articles that are produced per time unit, the shorter the time period necessary to achieve the desired number of produced absorbent articles. Due to the demands from customers, the quality of the produced articles is of course highly important. Moreover, a high production quality reflects upon the economy of the process, since it results in a low number of deficient absorbent articles which have to be discarded, thus keeping the waste to a minimum. Another important reason for minimizing the waste is that the manufacturer normally has to pay a fee for waste management, i.e., waste disposal. Furthermore, the waste involves a direct cost as a result of the loss of material.
A number of process methods have been proposed in order to meet the above mentioned demands. The most common way to reduce waste has been to manufacture the absorbent article in separate parts and to assemble the parts in a marriage point in the production line. However, a problem with this method is that the production is slow. In addition, there is an evident risk of assembling the parts incorrectly, resulting in deficient products and an increase in the production waste.
In order to overcome the problems associated with the production of absorbent articles from separately formed parts, a number of ways have been suggested. EP 0797970, for example, shows a process for manufacturing a sheet member forming a part of a disposable garment. A web intended to be used as a topsheet or a backsheet in a disposable garment and defining a front and a back section and a crotch section extending therebetween is continuously fed in its longitudinal direction. The web is divided in two halves along a longitudinally extending cutting line describing a wave-shaped curve approximate to a sine curve. In this manner, two webs are obtained. These two webs are moved in their transverse direction, resulting in a predetermined spacing between the webs. Moreover, one of the two webs is longitudinally shifted relatively to the other by a half period causing the webs to overlap at repeated intervals. Thereafter, the two webs are joined together in their overlapping regions. Thus, the two webs form a recombined web which is cut at intervals corresponding to the length of a wave period with a pair of overlapping regions arranged in the middle of each such wave period. In this manner, a topsheet or a backsheet can be manufactured without any waste pieces having to be cut therefrom.
Even though this process does not leave any waste, there are still some problems connected with the process. For example, the longitudinal shifting of one of the two webs slows down the manufacturing process. Further, both halves of the web are formed from the same material. Thus, in order to produce an absorbent article having special features such as different elasticity in different parts of the article (in order to conform better to the body of a user) additional components such as elastic material have to be applied to the web, either before or after the assembling of the two webs. Furthermore, since the web is divided in two halves along a longitudinally extending cutting line, it is necessary to provide special means in the process in order to keep the two halves in a similarly stretched state as before the division. If no stretching means are present, the two web halves may wrinkle or become distorted in some other way before the web halves are shifted and rejoined, which of course may result in a defective final product.
Thus, there still exists a need for an improved manufacturing process for absorbent articles. An objective of the invention is to provide a better and cheaper product, by offering a production line with a high volume of production and a high degree of productive power and with as little waste as possible.